I’m not sure about this. I can’t think of many villains I love, or love to hate. The two who do pop up are Miss Slighcarp in The Wolves of Willoughby Chase and Ginevra, the Queen in The Stolen Lake, both by Joan Aiken.
Who else? I’m thinking hard and … OK …
Mrs Coulter in His Dark Materials (Philip Pullman).
Count Dracula (Bram Stoker).
Mrs Danvers in Rebecca (Daphne du Maurier).
The White Witch in C.S. Lewis’s The Lion, The Witch and the Wardrobe.
Paul Emmanuel in Villette by Charlotte Bronte. What a pig!
Fanny Dashwood in Sense and Sensibility by Jane Austen. Not a major villain, but so manipulative and mean.
Beaver Hateman in the Uncle series by J. P. Martin.
Mrs Lancaster in By the Pricking of My Thumbs by Agatha Christie.
Huh that was weird and pretty half-hearted. All great books anyway. Read them, for the villains/’villains’, or just read them.